Fetal cells that enter the mother's blood stream during pregnancy can be recovered by charge flow separation (CFS), a method that obviates the risks associated with amniocentesis and chorionic villus sampling. The long-term objective of this project is development of a commercial system for prenatal screening and diagnosis based on recovery by CFS of fetal nucleated red blood cells (NRBC). The aims of the project are: (I) to increase further the speed and efficiency of CFS, and to decrease disposable costs: (II) to test CFS in the screening of common aneuploidies such as trisomy 13, 18, and 21, and to evaluate the specificity and sensitivity of the screening method; (III) to ascertain the life span of fetal NRBC in the maternal circulation; (IV) to culture CFS-processed fetal NRBC, and to discriminate between female fetal NRBC and maternal NRBC after recovery. For analysis of results, the processed fractions will be tested by FISH and primed in situ labeling (PRINS) for sex- chromosome-complement and the common aneuploidies; the results will be compared with those obtained after conventional cytogenetic analysis. Cultures will be evaluated for paternal DNA sequences and for karyotype. With further development, CFS could enable early diagnosis of a broad spectrum of congenital abnormalities, without risk to fetus or mother. Because the different cell types exhibit characteristic surface charge densities and distinctive mobilities in moving fluids, results with CFS are consistent and reproducible, facilitating experimental design and interpretation. Pretreatment of maternal blood samples with antibody is unnecessary. The method is rapid. The recovered cells are viable and the numbers of fetal NRBC obtained are substantially greater than the numbers obtained after separation by other methods. PROPOSED COMMERCIAL APPLICATION: Not available.